It's possible, and you've identified an advantage of doing so.
Luckily, users don't find new threads or posts only by viewing specific forums. A good number of users (a majority?) use the New Posts or the Spy features, which display the most recent activity regardless of forum. Also, when you use the Advanced Search page, you can click the top-level iOS forum to search across all of its subforums at once when a specific topic interests you.